模拟函数
Mock functions are also known as "spies", because they let you spy on the behavior of a function that is called indirectly by some other code, rather than only testing the output. You can create a mock function with jest.fn()
. If no implementation is given, the mock function will return undefined
when invoked. 你可以通过 jest.fn()
创建 mock 函数。 如果没有提供实现,调用模拟函数将返回 undefined
。
The TypeScript examples from this page will only work as documented if you explicitly import Jest APIs:
import {expect, jest, test} from '@jest/globals';
Consult the Getting Started guide for details on how to setup Jest with TypeScript.
方法
- 参考
mockFn.getMockName()
mockFn.mock.calls
mockFn.mock.results
mockFn.mock.instances
mockFn.mock.contexts
mockFn.mock.lastCall
mockFn.mockClear()
mockFn.mockReset()
mockFn.mockRestore()
mockFn.mockImplementation(fn)
mockFn.mockImplementationOnce(fn)
mockFn.mockName(name)
mockFn.mockReturnThis()
mockFn.mockReturnValue(value)
mockFn.mockReturnValueOnce(value)
mockFn.mockResolvedValue(value)
mockFn.mockResolvedValueOnce(value)
mockFn.mockRejectedValue(value)
mockFn.mockRejectedValueOnce(value)
mockFn.withImplementation(fn, callback)
- Replaced Properties
- TypeScript Usage
参考
mockFn.getMockName()
Returns the mock name string set by calling .mockName()
.
mockFn.mock.calls
An array containing the call arguments of all calls that have been made to this mock function. Each item in the array is an array of arguments that were passed during the call. Each item in the array is an array of arguments that were passed during the call.
For example: A mock function f
that has been called twice, with the arguments f('arg1', 'arg2')
, and then with the arguments f('arg3', 'arg4')
, would have a mock.calls
array that looks like this:
[
['arg1', 'arg2'],
['arg3', 'arg4'],
];